Modulation of leaf attributes and water use efficiency in Quercus suber along a rainfall gradient

Abstract

The aim of our study was to assess the intraspecific variation of a range of leaf attributes and carbon isotope discrimination (D), in Quercus suber, along an 800 mm rainfall gradient in Portugal. We measured specific leaf area (SLA), leaf thickness (LT) and density, and used leaf carbon isotope content as an integrated record of water use efficiency. The values of SLA of Q. suber were strongly, positively correlated with rainfall, decreasing as rainfall decreased. This reduction was mainly driven by LT, which was tightly correlated with SLA (R = -0.80, P \ 0.001), and steadily increased with declining rainfall. The significant increase in carbon isotope discrimination towards the wetter end of the gradient, with a difference of 4.2% in D between the two extremes, suggests a strong adjustment of leaf gas exchange to water availability. Leaf changes associated with precipitation in Q. suber thus seem to influence water economy, since reduction of SLA with the increase of LT with aridity improves water use efficiency. These data suggest that this evergreen tree species relies on its foliage plasticity and physiology to overcome water shortage.

Using hydrogel and clay to improve the water status of seedlings for dryland restoration

“…This result agrees with Damesin et al (1997), who observed lower δ 13 C leaf in Q. ilex and Q. pubescens on the wettest sites (1,134 mm) than on the driest sites (663 mm). In terms of carbon isotope discrimination (Δ leaf ), similar results have been reported by Goveiras and Freitas (2008). Both authors found a significant positive correlation between Δ leaf and the rainfall gradient (491-1,299 mm) of the Q. suber distribution in Portugal, and linked this result to an adjustment of gas exchange at leaf level according to water availability.…”

Warm and Fertile Sub-Humid Conditions Enhance Litterfall to Sustain High Soil Respiration Fluxes in a Mediterranean Cork Oak Forest

“…This supports our statement of a well-watered site based on the observed plasticity of this functional trait according to drought [61,62]. From this first observation, we then conclude that the carbon assimilated by trees is preferentially allocated to the aboveground biomass (leaf and stems), and the measured stem biomass is actually in the highest range of referenced forest sites in the Mediterranean basin [57,63,64], with impressive twig elongations (up to 28.5 cm) compared to [65] where apical twig elongations usually vary between 3.3 cm and 19.6 cm.…”

Leaf nitrogen is closely coupled to phenophases in a desert shrub ecosystem in China

“…With the expansion of the leaves, however, their shape became thin. It has been previously reported that SLA is positively correlated with precipitation (Gouveia and Freitas, 2009). Additionally, we found that leaf N was influenced by precipitation.…”